US8111227B2 - Liquid crystal display system capable of improving display quality and method for driving the same - Google Patents
Liquid crystal display system capable of improving display quality and method for driving the same Download PDFInfo
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- US8111227B2 US8111227B2 US11/927,679 US92767907A US8111227B2 US 8111227 B2 US8111227 B2 US 8111227B2 US 92767907 A US92767907 A US 92767907A US 8111227 B2 US8111227 B2 US 8111227B2
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- 239000004973 liquid crystal related substance Substances 0.000 title claims description 39
- 238000000034 method Methods 0.000 title claims description 29
- 230000008878 coupling Effects 0.000 claims abstract description 68
- 238000010168 coupling process Methods 0.000 claims abstract description 68
- 238000005859 coupling reaction Methods 0.000 claims abstract description 68
- 239000003990 capacitor Substances 0.000 claims abstract description 35
- 239000010409 thin film Substances 0.000 claims description 2
- 230000008054 signal transmission Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 8
- 230000003247 decreasing effect Effects 0.000 description 5
- 230000004075 alteration Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
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- 230000004048 modification Effects 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3648—Control of matrices with row and column drivers using an active matrix
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3685—Details of drivers for data electrodes
- G09G3/3688—Details of drivers for data electrodes suitable for active matrices only
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/04—Structural and physical details of display devices
- G09G2300/0421—Structural details of the set of electrodes
- G09G2300/043—Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0264—Details of driving circuits
- G09G2310/0297—Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0209—Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3614—Control of polarity reversal in general
Definitions
- the present invention relates to a liquid crystal display system and a method for driving the same, and more particularly, to a liquid crystal display system capable of improving display quality using a power line and a coupling capacitor and a method for driving the same.
- LCDs are flat displays characterized in thin appearance and low power consumption and have been widely used in various products, including personal digital assistants (PDAs), mobile phones, notebook/desktop computers, and communication terminals.
- PDAs personal digital assistants
- FIG. 1 schematically depicts a prior art thin film transistor (TFT) LCD 10 .
- the TFT LCD 10 includes a source driving circuit 12 , a gate driving circuit 14 , a plurality of data lines, gate lines Gate 1 -Gate m , demultiplexers DUX 1 -DUX n , and a plurality of pixel units.
- the data lines of the TFT LCD 10 includes red data lines R 1 -R n , green data lines G 1 -G n and blue data lines B 1 -B n .
- the pixel units of the TFT LCD 10 includes red pixel units P R1 -P Rn , green pixel units P G1 -P Gn , and blue pixel units P B1 -P Bn .
- the demultiplexers DUX 1 -DUX n include control switches SW R1 , SW G1 , SW B1 to SW Rn , SW Gn , SW Bn , respectively.
- Each pixel unit comprising a driving TFT switch and a capacitor, controls light according to charges stored in the capacitor.
- the gate driving circuit 14 generates scan signals for turning on/off the driving TFT switches of the pixel units via corresponding gate lines.
- the source driving circuit 12 generates data signals corresponding to images to be displayed by each pixel unit and sends the data signals to the pixels units via the control switches of corresponding demultiplexers.
- the TFT LCD 10 has a 1-to-3 demultiplexer structure, in which each demultiplexer distributes the data signals to three data lines.
- control signals CKH 1 , CKH 2 and CKH 3 By respectively sending control signals CKH 1 , CKH 2 and CKH 3 to the control switches SW R1 -SW Rn , SW G1 -SW GN , and SW B1 -SW Bn , data signals can be written into the pixel units via corresponding demulitiplexers in a predetermined sequence.
- FIG. 2 is a timing diagram illustrating a prior art row-inversion method for driving the TFT LCD 10 .
- V GATE+ and V GATE ⁇ represent the gate signals sent to a gate line during the positive- and negative-polarity driving periods, respectively.
- CKH 1 -CKH 3 represent the control signals sequentially applied to the control switches.
- V COM represents the common voltage of the TFT LCD 10 .
- V PIXEL+ (R), V PIXEL+ (G) and V PIXEL+ (B) respectively represent the voltage levels of the pixel units coupled to the red, green and blue data lines during the positive-polarity driving periods, which are respectively illustrated by dash lines, bold dash lines and dash-dot lines in FIG.
- V PIXEL ⁇ (R), V PIXEL ⁇ (G) and V PIXEL ⁇ (B) respectively represent the voltage levels of the pixel units coupled to the red, green and blue data lines during the negative-polarity driving periods, which are respectively illustrated by dash lines, bold dash lines and dash-dot lines in FIG. 2 as well.
- data are written into the pixel units in an R-G-B sequence by sequentially applying the control signals CKH 1 -CKH 3 for electrically connecting the source driving circuit 12 to corresponding red, green, or blue data lines.
- the control signals CKH 1 -CKH 3 for electrically connecting the source driving circuit 12 to corresponding red, green, or blue data lines.
- control switches respectively corresponding to the red, green and blue data lines in each demultiplexer are sequentially turned on. Therefore, the data signals generated by the source driving circuit 12 can be written into the pixel units coupled to the data lines via corresponding turned-on control switches, thereby changing the voltage levels of the red, green and blue pixel units accordingly.
- V GATE+ and V GATE ⁇ respectively represent the gate signals sent to the gate line Gate 2 during the positive and negative-polarity driving periods.
- V PIXEL+ (R), V PIXEL+ (G) and V PIXEL+ (B) respectively represent the voltage levels of the pixel units P R2 , P G2 , P B2 during the positive-polarity driving periods
- V PIXEL ⁇ (R), V PIXEL ⁇ (G) and V PIXEL ⁇ (B) respectively represent the voltage levels of the pixel units P R2 , P G2 , P B2 during the negative-polarity driving periods.
- the voltage V PIXEL+ (R) goes high accordingly (at T 1 in FIG. 2 ). Also, coupling voltages ⁇ V GR and ⁇ V BR due to the inherent capacitance between the data lines are generated when the data signals are transmitted to the green data line G 2 and the blue data line B 1 both adjacent to the red data line R 2 , causing the voltage V PIXEL+ (R) to increase further (at T 2 and T 3 in FIG. 2 ).
- liquid crystal voltages V LC+ (R), V LC+ (G), and V LC+ (B) respectively represent the differences between the common voltage and the voltage levels of the red, green and blue pixel units during the positive-polarity driving periods.
- liquid crystal voltages V LC ⁇ (R), V LC ⁇ (G), and V LC ⁇ (B) respectively represent the differences between the common voltage and the voltage levels of the red, green and blue pixel units during the negative-polarity driving periods.
- the illumination of a pixel unit is related to the absolute value of its liquid crystal voltage V LC .
- the liquid crystal voltages corresponding to the red, blue and green pixel units have the following relationship:
- An embodiment of such a display system comprises an LCD device including a plurality of gate lines; a plurality of data lines intersecting the plurality of gate lines; a plurality of first switches each having a first end coupled to a corresponding gate line and a second end coupled to a corresponding data line; a plurality of storage units each coupled to a third end of a corresponding first switch for receiving data from the corresponding data line; a first power line formed in parallel with the plurality of gate lines; and a plurality of first coupling capacitors each having a first end coupled to the first power line and a second end coupled to the corresponding data line.
- An embodiment of such a display method comprises turning on a first switch in a pixel unit coupled to a gate line for receiving a data signal from a corresponding data line; sequentially outputting data signals to a plurality of data lines via a demultiplexer; turning off the demultiplexer for keeping the plurality of data lines at a floating level; generating a coupling voltage by changing a voltage level of a power line from a first voltage level to a second voltage level, and transmitting the coupling voltage to a first data line of the demultiplexer via a coupling capacitor coupled between the power line and the first data line; and turning off the first switch in the pixel unit coupled to the gate line after generating the coupling voltage.
- Another embodiment of such a display method comprises turning on a switch in a pixel unit coupled to a gate line for receiving a data signal from a corresponding data line; outputting data signals to a plurality of data lines using a source driving circuit; terminating outputting the data signals to the plurality of data lines for keeping the plurality of data lines at a floating level; generating a coupling voltage by changing a voltage level of a power line from a first voltage level to a second voltage level, and transmitting the coupling voltage to a first data line via a coupling capacitor coupled between the power line and the first data line after keeping the plurality of data lines at the floating level; and turning off the switch in the pixel unit coupled to the gate line after generating the coupling voltage.
- FIG. 1 shows a prior art TFT LCD.
- FIG. 2 is a timing diagram illustrating a prior art row-inversion method for driving the TFT LCD of FIG. 1 .
- FIG. 3 shows a TFT LCD according to the present invention.
- FIGS. 4-6 are timing diagrams illustrating a method for driving the TFT LCD in FIG. 3 according to a first embodiment of the present invention.
- FIGS. 7-9 are timing diagrams illustrating a method for driving the TFT LCD in FIG. 3 according to a second embodiment of the present invention.
- FIG. 10 is a flowchart illustrating operations of the present driving methods when applied to TFT LCDs with demultiplexer structure.
- FIG. 11 is a flowchart illustrating operations of the present driving methods when applied to TFT LCDs without demultiplexer structure.
- FIG. 12 is a diagram illustrating a display system according to another embodiment of the present invention.
- FIG. 3 schematically depicts a TFT LCD 30 according to the present invention.
- the TFT LCD 30 includes a source driving circuit 32 , a gate driving circuit 34 , a control circuit 36 , power lines V 1 and V 2 , a plurality of coupling capacitors C R1 , C G1 , C B1 , C R2 , C G2 , and C B2 , a plurality of data lines, gate lines Gate 1 -Gate m , demultiplexers DUX 1 -DUX n , and a plurality of pixel units.
- the data lines of the TFT LCD 30 include red data lines R 1 -R n , green data lines G 1 -G n and blue data lines B 1 -B n .
- the pixel units of the TFT LCD 30 include red pixel units P R1 -P Rn , green pixel units P G1 -P Gn , blue pixel units P B1 -P Bn .
- the demultiplexers DUX 1 -DUX n each include three control switches SW R1 , SW G1 , SW B1 to SW Rn , SW Gn , SW Bn , respectively.
- Each pixel unit comprising a driving TFT switch and a capacitor, controls light according to charges stored in the capacitor.
- the gate driving circuit 34 generates scan signals for turning on/off the driving TFT switches in the pixel units via corresponding gate lines.
- the source driving circuit 32 generates data signals corresponding to images to be displayed by each pixel unit and sends the data signals to the pixels units via the control switches of corresponding demultiplexers.
- the coupling capacitors C R1 , C G1 and C B1 are coupled between the power line V 1 and corresponding red, green, blue data lines respectively.
- the coupling capacitors C R2 , C G2 and C B2 are coupled between the power line V 2 and corresponding red, green, blue data lines respectively.
- the voltage levels of the power lines V 1 and V 2 are controlled by the control circuit 36 .
- the TFT LCD 30 has a 1-to-3 demultiplexer structure, in which each demultiplexer distributes the data signals to three data lines.
- each demultiplexer distributes the data signals to three data lines.
- control signals CKH 1 , CKH 2 and CKH 3 to the control switches SW R1 -SW Rn , SW G1 -SW Gn , and SW B1 -SW Bn , the data signals can be written into the pixel units via corresponding demulitiplexers in a predetermined sequence.
- FIGS. 4-6 are timing diagrams illustrating a method for driving the TFT LCD 30 according to a first embodiment of the present invention.
- V GATE+ and V GATE ⁇ represent the gate signals sent to a gate line during the positive- and negative-polarity driving periods, respectively.
- CKH 3 -CKH 1 represent the control signals sequentially applied to the control switches.
- V C1 and V C2 represent the voltage levels of the power lines V 1 and V 2 , respectively.
- V COM represents the common voltage of the TFT LCD 30 .
- V PIXEL+ (B), V PIXEL+ (G) and V PIXEL+ (R) respectively represent the voltage levels of the pixel units coupled to the blue, green and red data lines during the positive-polarity driving periods, which are respectively illustrated by dash lines, bold dash lines and dash-dot lines in FIGS. 4-6 .
- V PIXEL ⁇ (B), V PIXEL ⁇ (G) and V PIXEL ⁇ (R) respectively represent the voltage levels of the pixel units coupled to the blue, green and red data lines during the negative-polarity driving periods, which are respectively illustrated by dash lines, bold dash lines and dash-dot lines in FIGS. 4-6 as well.
- data are written into the pixel units in a B-G-R sequence by sequentially applying the control signals CKH 3 -CKH 1 for electrically connecting the source driving circuit 32 to the blue, green, and red data lines.
- the TFT driving switches in the pixel units coupled to the gate line are turned on so that the capacitors in the pixel units coupled to the gate line can be electrically connected to corresponding data lines.
- V GATE+ and V GATE ⁇ respectively represent the gate signals sent to the gate line Gate 2 during the positive- and negative-polarity driving periods.
- V PIXEL+ (B) represents the voltage level of the pixel units P B2 during the positive-polarity driving periods
- V PIXEL ⁇ (B) represents the voltage level of the pixel units P B2 during the negative-polarity driving periods.
- the voltage level V PIXEL+ (B) of the pixel units P B2 increases three times when the control signals CKH 3 -CKH 1 have high voltage levels: the first voltage raise (at T 1 in FIG.
- the second voltage raise (at T 2 in FIG. 4 ) is due to the coupling voltage caused by the inherent capacitance between the data lines when the data signal is transmitted from the source driving circuit 32 to the green data line G 2 adjacent to the blue data line B 2 ;
- the third voltage raise (at T 3 in FIG. 4 ) is due to the coupling voltage caused by the inherent capacitance between the data lines when the data signal is transmitted from the source driving circuit 32 to the red data line R 3 adjacent to the blue data line B 2 .
- the voltage level V PIXEL ⁇ (B) of the pixel units P B2 drops three times when the control signals CKH 3 -CKH 1 have high voltage levels: the first voltage drop (at T 4 in FIG. 4 ) is due to the data signal transmitted from the source driving circuit 32 to the blue data line B 2 via the demultiplexer DUX 2 ; the second voltage drop (at T 5 in FIG. 4 ) is due to the coupling voltage caused by the inherent capacitance between the data lines when the data signal is transmitted from the source driving circuit 32 to the green data line G 2 adjacent to the blue data line B 2 ; the third voltage drop (at T 6 in FIG. 4 ) is due to the coupling voltage caused by the inherent capacitance between the data lines when the data signal is transmitted from the source driving circuit 32 to the red data line R 3 adjacent to the blue data line B 2 .
- FIG. 5 illustrates how the inherent capacitance influences the voltage level of the pixel units P G2
- FIG. 6 illustrates how the inherent capacitance influences the voltage level of the pixel units P R2 .
- the voltage levels V C1 and V C2 of the power lines V 1 and V 2 each remain at a constant level when writing data into the data lines.
- the voltages V C1 and V C2 are first kept at a high voltage level and a low voltage level, respectively.
- the voltage V C1 and V C2 can be altered in the first embodiment of the present invention.
- the voltage V C1 can be raised from a low level to a high level, while the voltage V C2 can be lowered from a high level to a low level.
- voltage differences are generated across the corresponding coupling capacitors, thereby providing coupling voltages to corresponding pixel units for compensating different degrees of color shifting.
- the voltage V PIXEL+ (B) obtained at T first in the positive-polarity driving periods has to be increased and the voltage V PIXEL ⁇ (B) obtained at T second in the negative-polarity driving periods has to be decreased.
- the voltage V C1 of the power line V 1 is raised from a low level to a high level in the first embodiment of the present invention for providing a corresponding coupling capacitor with a voltage difference ⁇ V 1 , which in turn provides a corresponding blue data line with a coupling voltage ⁇ V C1 — B . Therefore, the voltage V PIXEL+ (B) obtained at T first and the absolute value of the liquid crystal voltages V LC+ (B) of the blue pixel units can be increased at the same time.
- the voltage V C1 of the power line V 1 is lowered from a high level to a low level for providing a corresponding coupling capacitor with a voltage difference ⁇ V 1 , which in turn provides a corresponding blue data line with a coupling voltage ⁇ V C1 — B . Therefore, the voltage V PIXEL ⁇ (B) obtained at T second can be decreased and the absolute value of the liquid crystal voltages V LC ⁇ (B) of the blue pixel units can be increased at the same time.
- the adjusted voltages V PIXEL+ (B) and V PIXEL ⁇ (B) are illustrated by dashed lines.
- the voltage V PIXEL+ (B) obtained at T first in the positive-polarity driving periods has to be decreased and the voltage V PIXEL ⁇ (B) obtained at T second in the negative-polarity driving periods has to be increased.
- the voltage V C2 of the power line V 2 is lowered from a high level to a low level for providing a corresponding coupling capacitor with a voltage difference ⁇ V 2 , which in turn provides a corresponding blue data line with a coupling voltage ⁇ V C2 — B . Therefore, the voltage V PIXEL+ (B) obtained at T first and the absolute value of the liquid crystal voltages V LC+ (B) of the blue pixel units can be decreased at the same time.
- the voltage V C2 of the power line V 2 is raised from a low level to a high level for providing a corresponding coupling capacitor with a voltage difference ⁇ V 2 , which in turn provides a corresponding blue data line with a coupling voltage ⁇ V C2 — B . Therefore, the voltage V PIXEL ⁇ (B) obtained at T second can be increased and the absolute value of the liquid crystal voltages V LC ⁇ (B) of the blue pixel units can be decreased at the same time.
- the adjusted voltages V PIXEL+ (B) and V PIXEL ⁇ (B) are illustrated by bold dashed lines.
- the dashed lines represent the voltages V PIXEL+ (B) and V PIXEL ⁇ (B) after being adjusted using the power line V 1 and the corresponding coupling capacitors
- the bold dashed lines represent the voltages V PIXEL+ (B) and V PIXEL ⁇ (B) after being adjusted using the power line V 2 and the corresponding coupling capacitors.
- the values of the coupling voltages ⁇ V C1 — B and ⁇ V C — B are related to the capacitances of the corresponding coupling capacitors and the voltage differences ⁇ V 1 and ⁇ V 2 .
- the absolute values of the liquid crystal voltages V LC+ (B) and V LC ⁇ (B) of the blue pixel units can be adjusted flexibly by applying different voltage differences ⁇ V 1 and ⁇ V 2 to the power lines V 1 and V 2 , or by using coupling capacitors having different capacitances.
- the absolute value of the adjusted liquid crystal voltages V LC — UP (B) can be larger than that of the original liquid crystal voltages V LC+ (B).
- the absolute value of the adjusted liquid crystal voltages V LC — DOWN (B) can be smaller than that of the original liquid crystal voltages V LC+ (B).
- the present invention can compensate color shifting of the blue pixel units flexibly.
- the dashed lines represent the voltages V PIXEL+ (G) and V PIXEL ⁇ (G) when the user wants to increase the liquid crystal voltages of the green pixel units
- the bold dashed lines represent the voltages V PIXEL+ (G) and V PIXEL ⁇ (G) when the user wants to decrease the liquid crystal voltages of the green pixel units.
- the dashed lines represent the voltages V PIXEL+ (R) and V PIXEL ⁇ (R) when the user wants to increase the liquid crystal voltages of the red pixel units
- the bold dashed lines represent the voltages V PIXEL+ (R) and V PIXEL ⁇ (R) when the user wants to decrease the liquid crystal voltages of the red pixel units.
- FIGS. 4-6 are timing diagrams illustrating a method for driving the TFT LCD 30 according to a second embodiment of the present invention.
- data are written into the pixel units in an R-G-B sequence by sequentially applying the control signals CKH 1 -CKH 3 for electrically connecting the source driving circuit 32 to the corresponding red, green and blue data lines sequentially.
- the voltages V C1 and V C2 of the power lines V 1 and V 2 each remain at a constant level when writing the data signals into the data lines in the second embodiment of the present invention.
- the voltages V C1 and V C2 of the power lines V 1 and V 2 can be altered after writing data into a last data line controlled by a demultiplexer and before a corresponding gate signal goes low. Therefore, voltage differences across the corresponding coupling capacitors can be generated, thereby providing coupling voltages to corresponding pixel units for compensating different degrees of color shifting.
- the values of the coupling voltages are related to the capacitances of the corresponding coupling capacitors and the voltage differences ⁇ V 1 and ⁇ V 2 .
- the absolute values of the liquid crystal voltages can be adjusted flexibly by applying different voltage differences ⁇ V 1 and ⁇ V 2 to the power lines V 1 and V 2 , or by using coupling capacitors having different capacitances.
- the absolute value of the adjusted liquid crystal voltages V LC — UP (B) can be larger than that of the original liquid crystal voltages V LC+ (B). Or, the absolute value of the adjusted liquid crystal voltages V LC — DOWN (B) can be smaller than that of the original liquid crystal voltages V LC+ (B).
- the absolute value of the adjusted liquid crystal voltages V LC — UP (G) can be larger than that of the original liquid crystal voltages V LC+ (G). Or, the absolute value of the adjusted liquid crystal voltages V LC — DOWN (G) can be smaller than that of the original liquid crystal voltages V LC+ (G).
- the absolute value of the adjusted liquid crystal voltages V LC — UP (R) can be larger than that of the original liquid crystal voltages V LC+ (R).
- the absolute value of the adjusted liquid crystal voltages V LC — DOWN (R) can be smaller than that of the original liquid crystal voltages V LC+ (R).
- FIG. 10 depicts a flowchart illustrating operations of the present driving methods when applied to TFT LCDs with a demultiplexer structure.
- the flowchart in FIG. 10 includes the following steps:
- Step 102 turn on the switches in the pixel units coupled to a gate line for receiving data signals from corresponding data lines;
- Step 104 sequentially output the data signals to a plurality of data lines via a demultiplexer
- Step 106 generate a coupling voltage by changing a voltage level of a power line from a first voltage level to a second voltage level when the data lines have a floating level after outputting the data signals to a last data line of the demultiplexer, and transmitting the coupling voltage to a data line via a coupling capacitor coupled between the power line and the data line;
- Step 108 turn off the switches in the pixel units coupled to the gate line after generating the coupling voltage.
- the first and second embodiments of the present invention illustrated in FIGS. 4-9 can be applied to TFT LCDs having a 1-to-3 demultiplexer structure, as well as other structures such as a 1-to-6 or a 1-to-12 demultiplexer structure, etc.
- the present invention can also be applied to TFT LCDs without a demultiplexer structure. If data are written into the pixel units directly from the source driving circuit on a 1-to-1 basis instead of via a demultiplexer, no control switch is required and therefore no control signal is provided. The data lines need to have floating voltage levels when coupling voltages are generated using the power line.
- FIG. 11 depicts a flowchart illustrating operations of the present driving methods when applied to TFT LCDs without a demultiplexer structure. The flowchart in FIG. 11 includes the following steps:
- Step 112 turn on the switches in the pixel units coupled to a gate line for receiving data signals from corresponding data lines
- Step 114 output the data signals to the data lines via a source driving circuit
- Step 116 terminate outputting the data signals to the data lines for keeping the data lines at a floating level
- Step 118 generate a coupling voltage by changing a voltage level of a power line from a first voltage level to a second voltage level when the data lines have a floating level, and transmitting the coupling voltage to a data line via a coupling capacitor coupled between the power line and the data line;
- Step 110 turn off the switches in the pixel units coupled to the gate line after generating the coupling voltage.
- the present invention provides display devices and driving methods capable of improving display quality.
- the present invention can be applied to TFT LCDs with/without a demultiplexer structure and implemented with different driving sequences such as dot-, row-, or column-inversion. Different degrees of color shifting can be compensated in a flexible way.
- the display system can be a display device 40 or an electronic device 2 .
- the display device 40 can include the TFT LCD 30 in FIG. 3 , or can be integrated into the electronic device 2 .
- the electronic device 2 can include the display device 40 and a controller 50 .
- the controller 50 electrically connected to the display device 40 , can provide an input signal (such as an image signal), based on which the display device 40 can display images.
- the electronic device 2 can include devices such as mobile phones, digital cameras, PDAs, notebook/desktop computers, televisions, displays for automobiles, or portable DVD players.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Liquid Crystal Display Device Control (AREA)
- Liquid Crystal (AREA)
Abstract
Description
Claims (17)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN2006101607765A CN101191923B (en) | 2006-12-01 | 2006-12-01 | Liquid crystal display system capable of improving display quality and related driving method |
CN200610160776 | 2006-12-01 | ||
CN200610160776.5 | 2006-12-01 |
Publications (2)
Publication Number | Publication Date |
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US20080129906A1 US20080129906A1 (en) | 2008-06-05 |
US8111227B2 true US8111227B2 (en) | 2012-02-07 |
Family
ID=39319617
Family Applications (1)
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US11/927,679 Expired - Fee Related US8111227B2 (en) | 2006-12-01 | 2007-10-30 | Liquid crystal display system capable of improving display quality and method for driving the same |
Country Status (4)
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US (1) | US8111227B2 (en) |
EP (1) | EP1927976A3 (en) |
JP (1) | JP2008139860A (en) |
CN (1) | CN101191923B (en) |
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TWI353472B (en) * | 2007-10-22 | 2011-12-01 | Au Optronics Corp | Lcd with data compensating function and method for |
KR100938897B1 (en) * | 2008-02-11 | 2010-01-27 | 삼성모바일디스플레이주식회사 | LCD and its driving method |
WO2009127065A1 (en) | 2008-04-18 | 2009-10-22 | Ignis Innovation Inc. | System and driving method for light emitting device display |
TWI368805B (en) * | 2008-04-30 | 2012-07-21 | Au Optronics Corp | Liquid crystal display panel and pixel structure thereof |
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US9370075B2 (en) | 2008-12-09 | 2016-06-14 | Ignis Innovation Inc. | System and method for fast compensation programming of pixels in a display |
JP5399198B2 (en) | 2009-10-08 | 2014-01-29 | グローバル・オーエルイーディー・テクノロジー・リミテッド・ライアビリティ・カンパニー | Pixel circuit and display device |
CN101751896B (en) * | 2010-03-05 | 2013-05-22 | 华映光电股份有限公司 | Liquid crystal display device and driving method thereof |
CA2696778A1 (en) | 2010-03-17 | 2011-09-17 | Ignis Innovation Inc. | Lifetime, uniformity, parameter extraction methods |
US20140368491A1 (en) | 2013-03-08 | 2014-12-18 | Ignis Innovation Inc. | Pixel circuits for amoled displays |
US9351368B2 (en) | 2013-03-08 | 2016-05-24 | Ignis Innovation Inc. | Pixel circuits for AMOLED displays |
US9886899B2 (en) | 2011-05-17 | 2018-02-06 | Ignis Innovation Inc. | Pixel Circuits for AMOLED displays |
EP2945147B1 (en) * | 2011-05-28 | 2018-08-01 | Ignis Innovation Inc. | Method for fast compensation programming of pixels in a display |
US9747834B2 (en) | 2012-05-11 | 2017-08-29 | Ignis Innovation Inc. | Pixel circuits including feedback capacitors and reset capacitors, and display systems therefore |
US9336717B2 (en) | 2012-12-11 | 2016-05-10 | Ignis Innovation Inc. | Pixel circuits for AMOLED displays |
US9786223B2 (en) | 2012-12-11 | 2017-10-10 | Ignis Innovation Inc. | Pixel circuits for AMOLED displays |
US9721505B2 (en) | 2013-03-08 | 2017-08-01 | Ignis Innovation Inc. | Pixel circuits for AMOLED displays |
CA2894717A1 (en) | 2015-06-19 | 2016-12-19 | Ignis Innovation Inc. | Optoelectronic device characterization in array with shared sense line |
CA2873476A1 (en) | 2014-12-08 | 2016-06-08 | Ignis Innovation Inc. | Smart-pixel display architecture |
CA2886862A1 (en) | 2015-04-01 | 2016-10-01 | Ignis Innovation Inc. | Adjusting display brightness for avoiding overheating and/or accelerated aging |
US10373554B2 (en) | 2015-07-24 | 2019-08-06 | Ignis Innovation Inc. | Pixels and reference circuits and timing techniques |
US10657895B2 (en) | 2015-07-24 | 2020-05-19 | Ignis Innovation Inc. | Pixels and reference circuits and timing techniques |
CA2898282A1 (en) | 2015-07-24 | 2017-01-24 | Ignis Innovation Inc. | Hybrid calibration of current sources for current biased voltage progra mmed (cbvp) displays |
CA2908285A1 (en) | 2015-10-14 | 2017-04-14 | Ignis Innovation Inc. | Driver with multiple color pixel structure |
CN114175139B (en) * | 2020-05-13 | 2023-04-18 | 京东方科技集团股份有限公司 | Pixel driving method, display driving method and display substrate |
CN113920928B (en) * | 2021-10-29 | 2022-07-12 | 重庆惠科金渝光电科技有限公司 | Display panel driver and display device |
CN114637147B (en) * | 2022-03-30 | 2023-07-25 | 广州华星光电半导体显示技术有限公司 | Display panel and display device |
CN117275428A (en) * | 2023-10-11 | 2023-12-22 | 上海天马微电子有限公司 | Display panel and display device |
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Also Published As
Publication number | Publication date |
---|---|
EP1927976A3 (en) | 2009-08-19 |
JP2008139860A (en) | 2008-06-19 |
EP1927976A2 (en) | 2008-06-04 |
CN101191923B (en) | 2011-03-30 |
CN101191923A (en) | 2008-06-04 |
US20080129906A1 (en) | 2008-06-05 |
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